In that case, read this thread. It contains sevral solutions:
At my technical college I started programming in hex on an 1MHz intel 8008 single board computer with an astonishing amount of 512 bytes RAM.
A few month later I started with a bit of assembly on a motorola 6800. To give an indication: it was during the golden age of the Tandy TRS 80 Model 1 
Later on I did a bit of hacking on a 6502 though (Commodore 64) but I never owned one.